I personally would ask the teacher where the crayfish were "harvested" (lack of a better word :X) from. I have never seen an aquarium crayfish that resembles this little guy. Now it could just be the lighting (or lack there of) that's drowning out his colors. Do you live in a southern region with natural lakes/streams/rivers? It could be they were collected locally from the wild. I went to middle school in Southwest Florida and in science/biology class our teacher was ALWAYS pulling all kinds of critters out of the waterways and bringing them into the class. I fondly remember being in charge of feeding "Tilly" the Tilapia at one point ;D. If they were and they could provide the EXACT location of where they were harvested I would release the little guy back into the wild where he belongs. If he is NOT wild however (and I'm sure you already know this but I HAVE to add a disclaimer) DO NOT EVER RELEASE A NON-NATIVE SPECIES INTO LOCAL WATERS! I know sometimes it's tempting, especially when you cannot find a home for a "burden" aquatic animal. Also, you could always ask if the teacher would take it back? Maybe make it into a class pet? I hope you do find a home for the critter
I know from experience how frustrating an "uninvited" guest can be, trust me. I remember being a child and bringing a Comet Goldfish home from school, and the only fish tank we had was my father's pride and joy 250g Cichlid/Oscar community tank. Let's just say I cried for a couple of days after that one...
Hope you find a good home for him!
P.S I know this is probably none of my business, but forum rules states I HAVE to put my two cents into it, how many crayfish did the teacher give out? I know you have to sign a permission slip to be put into the running but how many children/parents/siblings/legal guardians sign that form knowing NOTHING about taking care of aquatic life? As I recall crayfish are pretty difficult to take care of. They do not eat flake food and I am pretty sure some (if not all) need a live source of food to survive. All I can think about is how many children/parents will take this little guy home and (without knowing) plop him into their small Goldfish/Betta/Guppy/Community tank and being devastated once this guy shreds small fish limb from limb. I'm sure you are one of the few who are educated enough in fish keeping to know that a crayfish isn't a community fish and to ask questions before haphazardly placing him wherever. Maybe mention to the teacher that in the future Crayfish aren't great critters to give to children as pets? Or maybe include on the permission form that these animals should NOT be housed with slow moving, non-aggressive, community fish and they do better either on their own or with larger, faster, short-finned fish in a LARGE (55g+) setting. Also maybe include some care instructions such as what they eat, simple water parameters, etc.?
Anyways, sorry for the rant
I hope everything works out for you!
Kentaaa